The service, called Windows OneCare, will provide automatically updated antivirus, anti-spyware and firewall protection. It also will include maintenance tools and backup capabilities. Microsoft said it plans to release a public beta version of OneCare later this year.
Symantec said it is ready to meet the challenge presented by Microsoft's entry into its market.
"We are prepared to compete on a combination of technology and the back-end infrastructure required to support it; the strength of our relationships with our channel partners; and most importantly, the strength of the relationships we have with tens of millions of consumers around the world," the company said in a prepared statement that noted its 15 years in the antivirus business.
Like Symantec, F-Secure touted its capabilities and track record but put an optimistic spin on Microsoft's move, which it said will generate additional security awareness.
"Microsoft's announcement is good news for F-Secure. They support the approach we have pioneered through the last five years in providing security as a live service. The additional exposure for the service approach will create new pull for such solutions," Risto Siilasmaa, F-Secure president and CEO, said in a statement.
But he noted that there is "a learning curve" to providing a live security service. The company also said that a comprehensive security service requires components that are missing from Microsoft's offering, including rootkit detection and features for zero-day protection.